In recent years, materials that use recyclable natural fibers have received attention due to increasing environmental awareness and for the purpose of substituting petroleum resources. Among natural fibers, a cellulose fiber having a fiber diameter of 10 to 50 μm, particularly, a wood-derived cellulose fiber (pulp), has been widely used mainly as a paper product.
In addition, microfibrous cellulose having a nanometer-scale fiber diameter is also known as a type of cellulose fibers, and the use thereof has been investigated in recent years for various applications.
Microfibrous cellulose is manufactured, for example, by a method of fibrillating a beaten pulp (Patent Document 1) or a method of fibrillating a cellulose raw material after treating the material with co-oxidizers such as N-oxyl and sodium hypochlorite (Patent Document 2).